The phase II clinical trial is designed to demonstrate the safety and effectiveness of an orally administered prodrug form of pyridoxal isonicotinoyl hydrazone (PIH) for the chronic treatment of iron overload. The hypothesis is that oral administration of the PIH prodrug will produce at least as much iron excretion as an infusion of subcutaneous desferri-oxamine in transfusion-dependent pts. with refractory anemias.